- There are many ways to write a given number
209,000,000
209 million
2.09 x 10^8
209 x 10^6
two hundred and nine million
Not all sources agree on how to handle these large numbers.
Recommendations:
- Numbers in the thousands shouold be written with the separating comma.
14,948
199,492
For consistency, retain the comma in four-digit numbers: 3,000 1,200 etc
- Numbers in the millions can be written in two ways: as numerals or as a numeral plus the word million
Use the numeral-and-word format when the last five or six digits are all zero:
2 million instead of 2,000,000
3.5 million instead of 3,500,000
150 million instead of 150,000,000
Use numerals when the last five or six digits are other than zero
5,936,999 instead of 5.936999 million
6,000,003 instead of 6.000003 million
- What about billions? Billion in the US means thousand million but a million million in other countries.
Numbers in the billions should be written as numerals.
If the readership is strictly US, use the numeral-and-word format: 1.7 billion
- When writing money, use a numeral followed by the word million or billion
$67 million instead of $67,000,000
- Numbers above the billions are usually written in numerals, not as numerals and words - the words
trillion, quadrillion, and quintillion are not familiar to the average reader
- Another method for writing numbers, scientific notation, expresses numbers using multiplication and exponents.
Scientific notation is helpful when writing extremely large numbers
1.5 X 10^9 instead of 1,500,000,000
10^12 instead of 1,000,000,000,000
- As a rule, it is better to use numerals than scientific notation. Scientific notation is compact, but its
format may be reproduced incorrectly (it's easier to type non-scientific notation)
7.5 million rather than 7.5 X 10^6 (like I'm having difficulty writing a superscript for the exponent)